The present patent application claims the right of priority under 35 U.S.C. xc2xa7119 (a)-(d) of German Patent Application No. 101 49 522.6, filed Oct. 8, 2001.
The present invention relates to a plastics-metal composite structural part and its use for frame structures. The invention relates in particular to a composite structural part produced by assembling profiled sections formed from high strength and high rigidity composite structural parts, in particular in a plastics-metal hybrid construction, in which the assembly of the profiled sections and the production of the composite structural parts is achieved simultaneously by the forming and shaping of thermoplastics moulding compositions. In the process, composite structural parts are produced having high strength and high rigidity components (e.g., of steel or composites) that are assembled with the aid of a thermoplastic material, and are additionally held in position and supported in shape by ribs or solid walls.
High strength joints of high load-bearing supporting members, profiled sections, sheets, etc. are often used in the manufacture of automobiles or machinery. In this connection supporting members of steel or aluminium are predominantly used that are welded or bonded to one another in the joining regions. To provide further stiffening of the joining sites, hereinafter also termed nodal points, cross-struts are typically integrated in the structure, or cast joints, for example of aluminium die castings, are employed. A further possibility is the use of semi-finished products consisting of composites (plastics material reinforced with long glass fibres), which are generally joined to one another. These semi-finished composites are generally joined to one another by forming laminates with joint elements that likewise consist of composites.
These procedures conventionally used in practice have the disadvantage that the assembly processes are time-consuming and permit only a limited dimensional accuracy and reproducibility in mass production runs. If cross-struts are used to provide additional stiffening of the joint elements, these generally must be thick-walled (1 to 3 mm) in order to prevent a mechanical failure due to bulging or buckling. Typical wall thickness"" of metal sheets used in the automobile industry are 0.7 to 1.2 mm in car production, and 0.7 mm to 3 mm in motor scooter production. This increases the weight of the structural part, which is contrary to the wishes of the manufacturer, particularly in vehicle production.
The object of the present invention is accordingly to provide a composite structural part having nodal points of the type mentioned in the background section that permits the high strength and high rigidity joining of supporting members and sheets as well as an economic assembly of semi-finished products and structural part components into structural parts. Also the fabrication of the joint elements should be accomplished with a high dimensional accuracy and reproducibility. A particular object is to arrange the profiled sections in the injection moulding tool so that they can be reinforced with plastics material in the tool by simple slide operations and then easily removed from the tool. The process for producing frame constructions for widely differing applications should thereby be simplified.
This object is achieved according to the invention in that reinforcing elements of high strength materials are used for joining the profiled sections and for stiffening the composite structural parts, the said elements being arranged in an interlocking manner in the joint region (connection site of the profiled sections). The joint region is then provided with a thermoplastic material that holds all the individual parts together and prevents a premature bulging or buckling of the high strength individual parts in the joint region. This object is furthermore achieved according to the invention in that at least two profiled sections have projecting regions at their ends that are surrounded by the reinforcing element.
In accordance with the present invention, there is provided a composite structural article comprising:
(a) at least one reinforcing element (2) having sized openings (20); and
(b) at least three profiled sections (1, 3, 4), wherein,
a portion of each profiled section is connected interlockingly with a portion of said reinforcing element (2),
at least two of said profiled sections have terminal portions each having a projecting region (5) that engages interlockingly with the sized openings of said reinforcing element (2) such that a portion of said reinforcing element (2) surrounds at least partially said projecting regions (5),
said profiled sections being further joined to said reinforcing element (2) by means of thermoplastic material (11, 13) injected in the region of each interlocking connection with said reinforcing element (2), and
one of said profiled sections (3) is in at least one of (i) an abutting relationship with at least two of said profiled sections (1, 4), and (ii) an interlocking relationship with at least two of said profiled sections (1, 4).
The features that characterize the present invention are pointed out with particularity in the claims, which are annexed to and form a part of this disclosure. These and other features of the invention, its operating advantages and the specific objects obtained by its use will be more fully understood from the following detailed description and the accompanying drawings in which preferred embodiments of the invention are illustrated and described.
Other than in the examples, or where otherwise indicated, all numbers or expressions, such a those expressing structural dimensions, etc, used in the specification and claims are to be under stood as modified in all instances by the term xe2x80x9cabout.xe2x80x9d